<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <div id="app">
    <input type="text" v-focus="100">
  </div>
 <script src="./vue.js"></script>
 <script>
    // 定义全局指令
    Vue.directive('focus', {
      inserted(el,binding){
        el.focus();
      }
    })
    const vm = new Vue({
      el: '#app'
    })
 </script>
</body>
</html>